Final answer:
The three types of RNA viruses are positive-sense single-stranded RNA viruses, negative-sense single-stranded RNA viruses, and double-stranded RNA viruses.
Step-by-step explanation:
The three types of RNA viruses are:
- Positive-sense single-stranded RNA viruses
- Negative-sense single-stranded RNA viruses
- Double-stranded RNA viruses
Positive-sense single-stranded RNA viruses have a genome that can serve directly as mRNA, while negative-sense single-stranded RNA viruses need to be replicated into positive-sense RNA before translation can occur. Double-stranded RNA viruses have two complementary strands of RNA, and mRNA is produced by transcription from these strands.